RDM Module Installation and Wiring
Installation of Remote Diagnosis Modbus Module
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Press the button of the cap on top of the contactor.
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Remove the cap. Keep it properly for future use.
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Place the RDM module on the top of the contactor and push it inwards to lock it automatically with a click.
NOTE: Ensure that RDM module is installed along both slots. -
Connect the cable to lock it automatically with a click.
Removal of Remote Diagnosis Modbus Module
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Press and hold the button on the side of the plug.
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Pull out the plug.
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Toggle the unlock trigger.
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Pull outwards to remove the RDM module.
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Put back the top cap.
Conductor Connection
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Take out the terminal from the packaging box.
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Insert inwards the conductor into the terminal.
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Tighten the screws by using a 2.5 mm flathead screwdriver at the right torque (0.2 N.m).
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Insert the terminal into the RDM module.
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Tighten the screws at the right torque (0.2 N.m).
Conductor Removal
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Loosen the screws to release the conductor from the terminal by using a 2.5 mm flathead screwdriver at the right torque (0.2 N.m).
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Pull the conductor out from the terminal.
Wiring Diagram
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Use a shielded twisted pair Modbus cable to reduce radiated emissions and improve shielding against external electromagnetic interference.
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A 120 Ω parallel resistor must be connected to D0–D1 when the RDM module is connected at the end of Modbus network.
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The maximum unshielded length of the Modbus cable is 30 mm.
Modbus Wiring in Daisy Chain Topology
The maximum length of the Modbus cable from the first PLC to the last RDM module is 15 meters. It is suggested to connect no more than 6 RDM modules in the daisy chain to achieve timely and responsive communication. The maximum number of RDM module in the daisy chain is 99.
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Wiring Characteristics
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Cable type |
Stripping length |
Number of conductors |
Section |
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Solid cable |
6–7 mm |
1 conductor without cable end |
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0.14–1.5 mm² |
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2 conductors with suitable dual end |
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0.14–0.5 mm² |
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Flexible cable |
1 conductor with suitable cable end or sleeve |
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0.25-0.5 mm² |
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2 conductors with suitable dual sleeve |
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0.5 mm² |
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Modbus cable (shielded twisted pair cable) |
6–7 mm |
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0.14–1.5 mm² |
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NOTE:
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For more information about Modbus wiring and application, please refer to "MODBUS over Serial Line Specification & Implementation guide V1.1" on modbus.org.